The mystery: the secrets lurking in the dark water

Deep in the Loch Ard forest, in the foothills of Ben Lomond, is the secret waterfall known as the Black Linn. It's not that big or high, but the pool below is dark and foreboding and here, long before the arrival of the Forestry Commission, legend has it that Rob Roy McGregor hid from the soldiers. It was here, too, in time unknown, that a sheep rustler on the run from the authorities is rumoured to have dived off the top of the waterfall and never come up again. Even today, the few brave locals who defy the slightly oppressive atmosphere, and swim in the steep-sided pool, report feeling strangely panicky in the eerily cold water. No-one knows how deep it is. In Victorian days, when the waterpipe from Loch Katrine to Glasgow was under construction nearby, the off-duty labourers would head for the pool to catch salmon, which had headed upstream but could get no further, unable to pass the

waterfall. In 1953 the Black Linn was taken over by Hollywood for the filming of Rob Roy, the Highland Rogue, starring Richard Todd, Glynis Johns, and James Robertson-Justice. Not many people visit the Black Linn these days: few maps mark it and the path is faint.

The essentials

Distance: 5 miles (7 km)

Time: 2 hrs

Waymarked: No

Map: OS 57

How to get there: From Aberfoyle, follow the B829 west through Milton to the large layby at Ledard beside Loch Ard. Park here or continue to the edge of Loch Ard, turn left by the telephone box, and continue to a car park where the road ends.

ACCOMMODATION: Lots of B&Bs. Upmarket hotels are Forest Hills (01877 387277) and the Lake Hotel at Port of Menteith (01877 385258). Cobleland Campsite, run by Forest Enterprise, is popular.

WHERE TO EAT: If you want to avoid bar food (of which there is plenty), several cafes on Aberfoyle's main street offer value-for-money light meals.

Other things to do: The south side of Loch Ard and the Queen Elizabeth Forest Park visitor centre north of Aberfoyle offer a number of waymarked walks and cycle routes. From there, head over the twisty Duke's Pass to a steamship trip on

the Sir Walter Scott and lovely walks on carless roads along the side of Loch Katrine. Tourist Information Centre: Aberfoyle (01877 382352).

The route

1. From the Ledard car park walk west along the road and turn left at the telephone box. 2. Continue past houses to a track ascending above the west end of Loch Ard. 3. Turn sharp right at a crossroads, pass under a large aqueduct, then take the next track on the left overlooking the Duchray Water.

4. At the bridge over the burn a faint path on the left leads downstream - care is needed - to views over the Black Linn waterfall with its gouged pots and pools.

5. Return by the outward route.